energy and enzymes part 1 Flashcards
Free energy
Usable energy that can do work
Change in free energy calculated by:
deltaG= Gproducts-Greactants
When a polypeptide(any macromolecule) is broken down into its smaller monomers via hydrolysis, energy is released
What type of reaction is eating
Catabolic reaction
Catabolic reaction
Reaction that breaks down large molecules into smaller units
Hydrolysis reaction to break polymers down into monomers
Energy(that was stored in the bonds holding the monomers together) is released
Exergonic
Exergonic reactions
Reactions where energy is released
Products have lower energy than reactants
Spontaneous = delta G is <0
What type of reaction is the incorporation of amino acids
Anabolic reaction
Amino acids are absorbed through the intestine after you eat and digest food, and released into the blood
They are then taken up by cells and used to build new proteins
Anabolic reaction
Building larger molecules from smaller units
Endergonic reaction
A reaction that requires energy input
Products have higher energy than reactants
Delta G is positive
What is the energy currency of cells?
The nucleotide, ATP
Adenosine triphosphate
Why does atp have energy
There are three phosphates in an ATP molecule and phosphate groups are negatively charged
The negative charge between the phosphate groups that are held close together, is the reason that ATP has a lot of potential energy
How does ATP act as energy currency7
Energy trapped in gradients(H+) or covalent bonds can be captured by the synthesis of ATP from ADP
In cellular respiration the H+ gradient results in phosphorylation of ATP from ADP but ATP is used in many steps of cellular respiration to allow for phosphorylation of other substances
Features of ATP
3 negative charges from triphosphate group results in an enormous source of potential energy due to the groups repelling one another
ATP stores energy in the phosphate group covalent bonds
Hydrolysis of ATP releases energy to drive endergonic reactions
ATP is the building block for nucleotides
ATP phosphorylates targets
ATP is rechargeable
ADP can be phosphorylated to turn into ATP
Coupled reactions
Reactions where you use exergonic energy to drive endergonic processes
How can ATP help with transport of substances?
ATP can phosphorylate proteins to change their conformation and allow things to be transported
Ex: if ATP phosphorylates a transport protein in the phospholipid bilayer, it can cause it to go through a conformational change and transport solutes across the membrane
How do enzymes speed up reactions?
Reduce the activation energy required to start a reaction
Promote substrates into a transition state
Enzymes
Important to all organisms
Catalyze important cellular reactions
Found in small amounts
Not consumed during the reaction
Enzyme substrate complex
Substrates enter active sites of the complex and held there by weak interactions
The active site lowers the activation energy of the reaction
Substrates are converted to products
Products are released and active site is available for new substrates
How does pH affect proteins
Changes in pH can denature proteins and cause them to lose/change their function
overall equation of cellular respiration
C6H12O6 + 6o2 → 6co2 + +6H2O+energy(atp)
point of cellular respiration
- to metabolize carbohydrates to get energy
-enzymes catalyze the breakdown of macromolecules(glucose) into stored energy - we need this energy to fuel cellular functions
four stages of energy harvest
1.glycolysis
2.pyruvate oxidation
3.citric acid cycle
4.oxidative phosphorylation
redox reactions in cellular respiration
NADH and FADH2 are electron carriers that link all the stages of cellular respiration
they are oxidized and reduced in order to carry electrons in the process
why are there so many steps in cellular respiration
We dont want to explosively release all of the energy from glucose, we want to get a little bit of atp at a time
Glycolysis (phases and where it occurs)
occurs in two phases:
1.Energy investment stage
2.Energy harvesting stage
Occurs in cytoplasm
goal of glycolysis
oxidize glucose in ten steps
- produce pyruvate (2 3 carbon chains from 1 6 carbon chain)
glycolysis net reaction
glucose + NAD+ + 2ADP + 2Pi
–>
2 pyruvate + 2 NADH + 2H+ + 2ATP + 2H2O
ATP usage and gross from two phases of glycolysis
energy investment phase = use 2 ATP
energy harvesting phase = make 4 ATP + 2NADH
net gain of 2ATP
Substrate phosphorylation
Making ATP from ADP + Pi
Enzyme combines ADP + Pi
ATP has more potential energy than ADP + Pi
Structural features of mitochondria
2 membranes
Outer membrane
Inner membrane
Intermembrane space
In between the outer and inner membrane
Pyruvate oxidation
After glycolysis, a transport protein shuttles pyruvate into the mitochondrial matrix
Pyruvate is oxidized by coenzyme A to turn into acetyl CoA
In the process, CO2 is released and NAD+ is reduced into NADH
Occurs in mitochondrial matrix
Acetyl needs coA to get through intermembrane of mitochondria
Then the coA release from acetyl
makes 1nadh per pyruvate
Citric acid cycle
Aerobic cycle
Occurs in interspace of mitochondria/ matrix
Enzymes catalyze the reactions
Citric acid is oxidized in the cycle (CO2 released)
2 CO2 is released per cycle
6 nadh, 2 atp, 2 fadh2, 4 co2 per one glucose
Every nadh and fadh produces how many atp
Every nadh produces three atp
Every fadhs produces 2 atp
Oxidative phosphorylation
etc and chemiosmosis
Proteins of electron transport chain pump protons out of the matrix of the mitochondria into the intermembrane space
Create an electrochemical gradient
NADH and FADH2 carry electrons to electron transport chain and donate them
Proteins use the electrons that are donated to power their pumping of protons across the electrochemical gradient
They pass the electron from one protein to the next until it reaches the last electron acceptor, oxygen
Forms h2o
Chemiosmosis
Use concentration of protons to power ATP synthase
Adp and pi are put in motor which turns when proton goes through it, producing ATP
Oxidative phosphorylation
Fermentation
Nadh and fadh2 can’t donate electrons to the transport chain
Glycolysis can keep going
produces a small amount of ATP when oxygen isn’t available
fermentation in humans
instead of nadh being sent to etc from glycolysis, the nadh donates its electrons to pyruvate to form lactate then lactate uses its electrons to reduce NAD+ and the cycle continues
oxidizing NADH produces little bit of ATP
alcohol fermentation produces ethanol instead of lactate
Feedback inhibition of cellular respiration
how is cellular respiration monitored
When we dont have enough energy, we produce AMP which stimulates a protein that promotes glycolysis and cellular respiration
When we have enough atp this signals to inhibit the use of that same protein, stopping glycolysis and cellular respiration from occurring
Products inhibit or stimulate
